The UV sterilization is directed to a physical sterilization method using light and is concerned on a technology killing microorganism by preventing it from growing and differentiating in such a way to destroy microorganism DNA information by means of the operations of 254 nm wavelengths in UV waves.
The UV sterilization way has been generally used for the sake of the sterilization of microorganism in fluid (or waterborne microorganism). The fluid to be sterilized must have a certain level of UV transmissivity for the reasons that the sterilization UV wavelength is very short, 254 nm, so it can be easily absorbed by turbidity or chromaticity, which results in low transmissivity.
When the transmissivity of the UV sterilization with respect to fluid reaches 60% (or 40˜50% in some companies), it is judged to be economical. When the transmissivity of the fluid is below 40%, UV is not generally applied to the UV.
For these reasons, the sterilization of the fluid the transmissivity of which is low is almost dependent on heat. When the sterilization on the fluid by means of heat is performed, over energy costs a lot, and lots of side effects occur as some components in the fluid is destroyed by high heat.
The UV transmissivity represents the intensity that a UV with a wavelength of 254 nm transmits through a fluid filled in a 1 cm crystal cell, and the intensity is expressed in percentage. The transmissivity of UV is generally above 98% in case of a drinkable water from a spring, and 96% in case of a raw water from a tap, and 60˜70% in case of a wasting water from a sewage.
The transmissivity of UV grows lower when there is a substance formed in a benzene structure such as pentose or hexose like an organic substance or a sugar syrup which is a component among fluids which absorbs UV like Fe, Mn, etc.
A fluid having a low transmissivity is a green vegetable juice (kale, water parsley, pomegranate, carrot, etc.), fruit juice beverage (orange, apple, pomegranate, etc.), tree juice (painted maple sap, maple tree sap, etc.), alcohol drinks (traditional wine, Korean wine, apple wine, etc.), various health beverages, sauce and seasoning (soy sauce, permission vinegar, fructose, etc.), lubricant, medicine, other high density and UV non-transmittable liquid which needs sterilization.
In particular, the green vegetable juice is a juice from the vegetable as natural organic vegetables are collected and pressed by a press; however ordinary bacteria counting to 10,000˜100,000 (cfu/mL) per mL are found after pressing the vegetable. Most of the companies directly deliver to the customers within one day so as to prevent any spoilage during the distribution. The customers are guided to drink all the stuff after it is opened.
If the green vegetable juice is placed at a room temperature, lots of microorganism grows and the container becomes barrel-shaped in one day by means of the microorganism. In order to prevent the above mentioned problems, the sterilization of the microorganism is desperately needed, but the conventional art does not fully perform the sterilization by way of the UV.